Where does the weather come from?

Could you tell me where Weather Watcher Live needs to get to on the internet to retrieve what it needs? Are there a few urls? I want to try the program on some computers that have very limited internet access, so it would be a case of allowing the program access to only where it needs to go.

thanks

Weather Watcher Live needs to be able to access the following URLs:

http://www.weather.gov
http://www.weatherbug.com
http://www.wxbug.com
http://www.wunderground.com